Water heater

A water heater comprising:

• a fan;
• at least one burner that receives a supply of combustion air from the fan;
• a heat exchanger used for heat recovery;
• a combustion chamber case configured such that a combustion chamber of the burner is formed in the interior thereof and so as to be capable of guiding combustion gas generated by the burner to the heat exchanger;
• a unit case surrounding the combustion chamber case;
• and
• an air pressure chamber formed from a region on the outside of the combustion chamber case within the unit case and set at a higher pressure than the combustion chamber, wherein
• the unit case includes a unit case front portion and a unit case rear portion that are couplable to each other,
• the unit case front portion and the unit case rear portion can be assembled so as to sandwich the combustion chamber case and the heat exchanger from a front-rear direction thereof,
• a plurality of flange portions are provided on respective outer peripheries of the unit case front portion and the unit case rear portion,
• the unit case front portion and the unit case rear portion are coupled to each other by bringing the plurality of flange portions into contact with each other and performing crimping thereon,
• a bottom lid is attached to the unit case to block a lower opening portion of the unit case, and
• the fan and a drive motor thereof are housed in the unit case and mounted on the bottom lid of the unit case such that the fan and drive motor are disposed proximal the combustion chamber case.